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It’s currently late summer in the southern hemisphere of Triton, and it will be for a while. Seasons on Triton, Neptune’s largest moon, last over 40 years, with each pole spending 80 years in sunlight followed by 80 years of darkness.

So where is the best place to spend a (very, very, very) extended summer vacation on Triton?

We suggest Uhlanga, the southern polar region of Triton, named after the marsh from which humanity was born in Zulu mythology. There you will find marvels worthy of any creation myth.

Bring your sunglasses. The icy surface of Triton reflects over 70 percent of the sunlight that hits it. You’ll walk through jutting uplifts of sparkling crystal scattering the light of a seemingly endless day.

But the true wonder is the geysers. Triton is one of only four bodies in the solar system with volcanic activity and it is by far the coldest. Constantly active geysers eject material that snap-freezes in the cold sky and scatters it as glistening nitrogen snow.

This is not a soft settling of snow either. The winds on Triton nearly reach the speed of sound. Thankfully, it’s unlikely to knock you over, as Earth’s atmosphere is 50,000 times more dense than Triton’s.

All of this outgassing creates a constant haze in the summer, extending up to 30 kilometers from the surface. It’s composed largely of hydrocarbons and nitriles created by a methane reaction with both solar and stellar ultraviolet light. The sky is also patched with clouds in the form of nitrogen ice particles. But even through the haze the great blue planet Neptune dominates the sky. Triton is about the same distance from Neptune as Luna is from Earth, but Neptune is 17 times the mass of Earth.

The icy geysers are not the only thing that makes Triton strange place. Its orbit around Neptune is in reverse.

This is unique. Triton is the only large moon in the solar system (and, thus, the only one we know about) that’s in a retrograde orbit. Some outer, irregular satellites of Jupiter, Saturn, and Uranus travel in retrograde, but they’re mostly oddly-shaped, smaller rocks. The absolute largest of them, Phoebe (a pock-marked asteroid revolving around Saturn), has 0.03 percent of the mass of Triton. The other objects in retrograde also tend to be on highly-irregular orbits, but Triton’s orbit around Neptune is a nearly perfect circle, with an eccentricity of almost zero.

This unusual arrangement suggests that Triton was once a dwarf planet, much like Pluto, that was then pulled from the Kupier belt by Neptune’s gravity and captured as a moon.

Pluto, however, will not join Triton. Because Pluto’s orbit occasionally passes within Neptune’s orbit (from 1979 to 1999 Pluto was closer to the Sun than Neptune), many people have wondered if the former member of the Nine will ever become a moon like Triton. But Pluto’s orbit takes it 17 degrees above and below the plane Neptune orbits on and the two never get within 100 million kilometers of each other.

Triton’s capture must have been a chaotic event, and it’s probably why Neptune has so few moons. Jupiter has 67 moons, Saturn has 62, Uranus 27, and Neptune only has 14… and most of those are small. For example, Uranus has four moons with a diameter of greater than 1000 kilometers (Ariel, Oberon, Titania, and Umbriel). Excluding Triton itself, Neptune has none that are even 500 kilometers in diameter.

It’s likely that Neptune was once like the other giants in our solar system, with its own suite of large moons. Then Triton came swinging around Neptune, knocking other moons out of orbit as its oceans of liquid water sloshed around the dwarf planet. It is likely that Triton at one point had liquid water because its post-capture eccentricity probably resulted in severe tidal heating. It could have remained fluid for billions of years as it slowly refroze and drifted into its quiet, nearly-perfect retrograde orbit.

It’s a reminder that the apparent serenity we see now in the solar system is because we’re only seeing a snapshot, a tiny piece of processes that occur on a cosmic scale.

All of our solar system’s planets, and moons – yes, even us – are survivors of this chaos arranged in strange and beautiful fashion, like a backward-orbiting-former-dwarf-planet-moon blasting sun-glowing nitrogen crystals into speed-of-sound-40-year-summer winds.

In the woods near my childhood home there was a cliff. I suppose it is more accurate to say there is a cliff — cliffs don’t move much on a scale of decades — but ‘was’ seems more appropriate because the actual size of the cliff does not represent the size that existed in my young mind. The fear of standing near the edge prevented any reasonable calculation of height.

But I could count. I could throw a rock and listen for how long it took for the ‘crack‘ sound to echo up from the canyon below. Being able to count out whole numbers before hearing the rock strike was almost as frightening as looking over the edge. Almost.

Despite what I may have imagined as a child, that cliff in the woods near home is not, in fact, the tallest cliff in the world. The greatest purely vertical drop is the 1.25 kilometer cliff on the side of Mount Thor in Canada. The greatest nearly vertical drop is a 1.34 km fall from the Trago Towers, a group of rock towers in the self-governing Pakistani territory of Gilgit-Baltistan. A fall from either would take approximately twenty seconds.

Not only is that an excruciatingly long time to fall, it is more than enough time to reach the human body’s terminal velocity in Earth atmosphere of 200 kph. [This depends, of course, on your preferred method of falling. A speed of 200 kph assumes a horizontal alignment. If you go nose-first, you can probably get it up to about 320 kph, assuming you have a particularly compelling reason to hit the Earth face-first at bullet-train speed.]

Neither Thor nor the Trago Towers come close to being the tallest cliff in the Solar System. The tallest is the Verona Rupes on Miranda, a moon of Uranus. If you were to look down from the sudden, shear edge of the rupes (Latin for “cliff”), you’d see a vertigo-inducing ten-kilometer drop.

Just why there is this giant cliff on Miranda is still studied and debated. It shouldn’t be there, given that Miranda is one of the smallest objects in the Solar System to be spherical under its own gravity. Yet Miranda is covered in mountains and cliffs. Perhaps it’s the result of crust rifting or cryovolcanic eruptions of icy magma. Or perhaps there was a single, massive collision with another moon, tearing Miranda asunder before reassembling into its current shape.

Whatever process created the massive mountain, a jump from the cliff’s edge would take a long, long time to complete. Thanks both to the distance and Miranda’s very, very low gravity, the fall would take a full eight minutes. Partially this is because of how slow the fall would be at the beginning.

Gravitational acceleration on Miranda is 0.079 meters per second squared. If you dove out from the cliff, it would appear momentarily as if you were hovering, floating still with the great cyan orb of Uranus above. The Sun would look like the star that it is – a bright star, certainly, but just a star. If you looked hard enough you could probably pick out Uranus’s other four large moons: Ariel, Umbriel, Titania, and Oberon.

Then the fall would start.

Slow at first. It would take about twelve or thirteen seconds just to get to the lazy pace of one meter per second. But with no air resistance to speak of, you’d just keep getting faster and faster, and ten kilometers is a long way to go. Faster and faster. By the time you’re near the ground, you’d be traveling at over 144 km per hour (90 mph).

Survival is possible. After all, 144 kph is fast, but not as fast as you’d be traveling during the much shorter fall from Mount Thor. All that’s needed is something that could cushion a 90 mph impact. A parachute wouldn’t help, as there’s no atmosphere to catch with it. A large, quick-inflating airbag might suffice. Or some kind of retrorocket boots, like an Iron Man-type thing.

The great ringed gas giant Saturn has sixty-two moons. But ninety-six percent of the mass of those moons is found in one object: Titan.

At 5,150 km across, it’s diameter is greater than the planet Mercury. It is three-quarters the size of Mars and fifty percent larger than Earth’s moon, Luna.

Titan is the only place in the solar system – apart from Earth – where you’ll find liquid on the surface and it is the only known natural satellite with a thick atmosphere. In fact, the atmosphere is so dense and extends so far from the moon’s surface that its opaque clouds caused astronomers for many, many years to mistakenly call Titan the largest moon in the solar system. (Take away Titan’s shroud and Ganymede, a moon of Jupiter, has a diameter that is two percent greater).

The massive moon is unlike any place in the solar system. It’s worth a visit. But before you land on Titan, be sure to spend some time in the clouds.

Hovering above Titan, you may be surprised by the sky that surrounds you. Though it appears a near uniform yellow from above, the scattering of light in the atmosphere makes it appear an Earthly blue while you’re in the clouds themselves.

You’ll also want to spend some time up there before your descent so you can get a good look at Saturn.

Saturn will be huge in the sky above. From Titan you can see at the swirling, golden storms that race around the planet at speeds as high as 1,800 km/hr. It’s famous rings will appear as a wire-thin white line bisecting the great planet because Titan orbits edge-on with Saturn’s rings, as do most of the moons.

Once you’ve had your fill of Saturn, it’s time to descend into the yellow swirling clouds below, cutting through layer after layer of titian sky (titian as in the color, not the moon Titan (no, seriously, titian is a color (it’s a golden-orange-brown (no, it’s not called that because of Titan (it is a complete coincidence that Titan is titian in color (titian comes from the English name of Tiziano Vecelli, a sixteenth-century Italian painter (women in his paintings commonly have bright brownish orange hair))))))).

As the surface becomes visible through the fog, you’ll see dark streaks across the land. Much a Titan is desert, rolling black dunes of windblown ice crystals and ammonia, as well as hydrocarbons carried from the atmosphere to the surface by rain. But the dunes are not our destination. We are headed for Xanadu.

In the Xanadu region, an Australia-sized uplift, you’ll find river networks, hills, valleys, and the occasional large crater caused by an asteroid large enough to penetrate the thick atmosphere. Mountains are relatively small on most of Titan, but in Xanadu they’re as big as the Appalachians, most likely due to tectonism (shifting plates) and cryovolcanic (ice volcano) processes.

When you land, you’ll find the surface beneath your feet to be soft, almost like mud (quite a shift from the hard surfaces we’ve visited so far). But the mud is not created by water…

…or, rather, there is water, but the water isn’t the wet part. As it were. The surface temperature on Titan is 290 degrees below 0 F. That’s cold enough to make ice as hard as rock. And, indeed, the “rock” part of the mud is ice. The “wet” part is methane. CH4, more commonly known as natural gas. On Titan, natural gas is a liquid… and there is a lot of it. Lakes and rivers of it.

As you look about in the orange twilight glow created by the clouds, you’ll see a scattering of rocks and boulders on the muddy ground. These ice rocks are smooth and sit in depressions, like river rocks on Earth. That’s because they are river rocks.

Much like a desert on Earth, Titan has brief and intense wet seasons. Methane falls from the cold sky as rain, creating huge rushing rivers. Due to Titan’s low gravity, waves in the lakes and rivers would be seven times taller than waves on Earth. But they also move three times slower.

This sounds like ideal surfing conditions, but the low surface tension and relative low density of liquid methane might make the attempt… difficult. You can take a shot if you’re up for it, but we recommend instead trying something that you can’t do on Earth: fly.

Not hang-gliding, not a wing suit drop, we mean actual, human flight. The atmosphere on Titan is so thick and the gravity is so low that humans with properly designed wings strapped to their arms could get off the ground just by flapping. It takes some practice. And it carries a lot of risks. So if you’re feeling particularly adventurous, know what you’re getting into and ensure you’re properly equipped.

Speaking of equipment, night vision goggles are a must. Not only will the ability to see in infrared give you a clearer view of surface features, you’ll also be able to see a curious phenomenon only available on Titan.

It rains on Titan and where there’s rain, there are rainbows. Aside from Earth, Titan is the only other known place where rainbows can form. Due to the lack of direct sunlight, visible rainbows are rare, but infrared rainbows are very common. Since the rainbows are caused by methane and not water, the primary radius of each arc would be 49 degrees, as opposed to 42.5 (the index of refraction of liquid methane is 1.29, as opposed to 1.33 for water).

On Titan you get big rainbows. Or, rather, rather, methanebows.

They are quite beautiful. I’m actually composing a song about them.

Somewhere over the methanebow, way up high
There’s a land that I heard of once in a lullaby
Somewhere over the methanebow, skies are yellow
And the dreams that you dare to dream really do come true…o

Photograph No. 1: Cassini spacecraft on May 21, 2011, at a distance of approximately 1.4 million miles (2.3 million kilometers) from Titan – Photograph No. 2: Cassini spacecraft on March 31, 2005, at a distance of approximately 5,900 miles (9,500 kilometers) – Photograph No. 3: Image of Titan’s surface taken by the Huygens probe on January 14, 2005, at a distance of approximately… well, you know… ZERO miles (zero kilometers)

Hidden among millions of massive objects in the Asteroid Belt is a rare astronomical gem: an asteroid with two moons of its own.

Asteroid 87 Sylvia, named for the Roman mythical mother of twins Remus and Romulus, is an oblong rock averaging 286 kilometers in diameter. It’s twin moons are, of course, named Remus and Romulus.

Sylvia is an exceptionally low density asteroid. At least a quarter and probably more than half of its interior is empty space. At about 385 kilometers from tip to tip, there are plenty of weaving catacombs through 87 Sylvia to explore. Thanks to the light gravity of the asteroid, the caves can be traversed quite easily with huge leaps and bounds.

Though you can jump tremendous distances, you don’t have to worry about accidentally launching yourself into space. With an escape velocity of 138 meters a second, your giant leaps will carry you far, but will always bring you back to the surface. (Though… how gently depends largely on the nature of your leap. Please be cautious and utilize proper safety equipment for any bouncing space spelunking.)

Now that you know where to go, we can address the question of when.

Thanks to its twin moons, you can end your leaping cave exploration by finding a spot on the asteroid’s porous surface to watch a spectacular double (double!) eclipse.

A “double eclipse” sounds like it would be a rarity, but not on 87 Sylvia. Due to the asteroid’s relatively high rotation speed, a double eclipse is a surprisingly frequent occurrence. 87 Sylvia completes a rotation about once every five hours, Remus orbits its parent asteroid about once every day-and-a-half, and Romulus orbits 87 Sylvia about once every three-and-a-half days.

So, about once every three (Earth) years, Remus and Romulus come together in alignment between 87 Sylvia and the Sun. Each moon makes a nearly perfect eclipse of the other, as they each would look like they’re the same size from the surface (the farther one, Romulus, being larger than the inner moon, Remus).

This is not like a terrestrial eclipse. Romulus and Remus are relatively small (about 14 and 7 km in diameter, respectively), but they’re so close that they’ll appear to be huge to you, about twice as big as the Moon appears from Earth. The Sun, meanwhile, looks much, much smaller so far out.

Remus and Romulus totally devour the Sun in an eclipse. And with the light of the Sun converted into a soft halo around apparently massive twin spheres, the full sky is visible.

You won’t see other asteroids. Despite popular imaginings of the Asteroid Belt, most asteroids are so far from each other that no other asteroids are visible from each other’s surfaces. In fact, a third of the mass of the Belt is in one object, the dwarf planet Ceres.

But you’ll see so, so many stars. You have to travel great distances on Earth and wait a very long time to see all the stars above and below the poles. The fast rotation of 87 Sylvia means you only have to wait a few hours to see every star in the sky. With no sun and no atmosphere, the double eclipse on 87 Sylvia gives you the clearest star-filled sky in the inner solar system.

Well, except for one very big object.

87 Sylvia is part of the Cybele Group, on the outer edges of the Belt, which means if it’s nearby in its orbit, Jupiter would dominate the sky. When they’re on the same side of the solar system, Jupiter is almost three times closer to 87 Syliva than it is to Earth. You should even be able to make out Jupiter’s biggest moons with just the naked eye.

While sitting in your viewing spot, if you reached down to pick up a rock or part of asteroid, it would likely crumble away. 87 Sylvia is dark, ancient rubble pile of the primordial pieces of the Solar System’s creation held together by the collective gravity of those rocks.

The Asteroid Belt is a strange place, and a window into its star system’s early days.

As the giant planets moved all about – and Jupiter causing the most damage – over 99 percent of the Asteroid Belt’s original mass was lost in the first 100 million years of the Solar System’s history.

It was a chaotic time. At one point there were two large, rocky planets passing around the Sun at the same distance. (They eventually ran into each other and created the Earth and the Moon.) Other planets fell into the Sun or were ripped free. No doubt there are entire planets from the early days of our Solar System out wandering between the stars, unknown lost worlds flung from the Sun’s gravity.

Eventually it all stabilized. Relatively speaking, of course. Though it appears stable, the Solar System is constantly changing. 87 Sylvia likely got its moons in a collision with another asteroid.

The truth is the chaos never stopped. The Solar System is so old, so massive, so complex, that we are only experiencing a moment of apparent stability. The Asteroid Belt is a reminder of that. Every time Jupiter passes by it stirs up the rocks.

Eventually all of this apparent order will scatter. But for now, as in every moment of a solar system’s evolution, there are perfectly balanced wonders to find.

Veiled in gold, Earth’s sister planet was once a tantalizing mystery. What lay below those clouds? Oceans? Jungles? Many imagined a lush garden world.

They were quite wrong. The mean surface temperature is 735 K (462 C, 863 F). Atmospheric pressure is ninety-two times that of Earth. The evocative descriptor “hellish” is often used to describe Venus.

But it is so very beautiful.

Eighty percent of the planet’s surface consists of overlapping lava plains, with hundreds and hundreds and hundreds of volcanoes spiking upward from the surface. On Earth there is only a single volcano greater than a hundred kilometers across (the Big Island of Hawai’i). Venus has one hundred and sixty-seven.

Not all are active at once (at least, not right now), but when active a Venusian volcano can create lava flows hundreds of kilometers long and tens of kilometers across. So plan your trip for a period of high volcanism.

As for where to sit and watch, we recommend the Alpha Regio region in Venus’s southern hemisphere. Don’t worry, it’s easy to spot.

The granite uplift is one thousand five hundred kilometers across and much lighter in color than the surrounding basalt plains. Alpha Regio is so large and distinct that it was the first surface feature to be identified by Earth-based radar.

There are several volcanoes in the plains surrounding the Alpha Regio, but your best bet is probably to find a lovely spot on the southwestern edge… especially if Eve Corona is active.

A corona is formed when plumes of rising magma push the crust upward into a dome which then collapses in the center, leaving a crown-shaped crater hundreds of kilometers across with tremendous flows of lava leaking out of its craggy edges. Coronea are a geologic feature unique to Venus, and quite spectacular when active. (The only other place in the solar system with remotely similar features is Uranus’s moon Miranda, which are probably formed by upwelling of warm ice.)

So if you’re there at the right time, you can sit above and watch the lava drift by. You’ll probably notice that the flow is smoother and much more viscous than terrestrial lava. The average surface temperature on Venus (863 F) is hotter than even the melting point of lead (622 F). That’s still cool enough to solidify the basalt, but at a bit slower pace. However, you’ll find that the rock beneath your feet should still be nice and sturdy, given that granite has a much higher melting point (well over 2000 F).

Heat will no doubt be an issue, but we still recommend finding a spot close to the lava flows. Visibility on the surface of Venus will be about three kilometers at the very most. As such, very little sunlight reaches the surface and everything will be covered in a dim, golden haze. Of course, the low lighting also gives a marvelous glow to the lava.

Plus, there will occasionally be brilliant flashes of light, especially around active volcanoes… due to acid lightning (real thing). Venus is one of four planets in the solar system that generates lighting – along with Earth, Jupiter, and Saturn. But unlike like those three, Venus does so without water. Instead, lightning is generated by clouds of sulfuric acid.

But though you’re going to deal with relatively low light, there’s no need to worry about the sun going down while you’re relaxing by the lava flow. ‘Time of day’ is a fairly useless concept on Venus. The planet completes a single retrograde rotation once every two hundred and forty-three Earth days. One Venusian day lasts longer than one Venusian year. It’s the slowest rotation of any planet in the solar system and the slow spin makes the planet highly spherical. (Earth is really more of an oblate spheroid.)

Once you’ve got your spot, you’ll need to weigh yourself down in order to keep that spot. Though conditions are relatively calm near the surface (especially compared to the violent upper-atmosphere), even a slow breeze is capable of knocking you over. The thick atmosphere means that each gust hits like a great wave. Some kind of wind-screen is advisable and do not attempt to walk against the wind. You will find it… inconvenient.

Along with the occasional massive lava flow, you’ll also observe some strikingly large craters. The craters will stand out because of how smooth the plains are around them and because there are no small craters at all. Only big ones. This is because of Venus’s dense atmosphere. Any rock not big enough to punch through burns up. In addition, volcanism tends to wipe away smaller surface features.

Venus is shaped and defined by volcanism. But though there is a great deal of activity, Venus has no tectonic plates. Or, rather, the entire crust is one giant plate.

On Earth, the plates move, carrying the continents with them. At fault lines, one plate is dragged under the other and new land is pulled up from below on the far side. No such subduction occurs on Venus. Instead, pressure slowly builds and builds, forcing volcanoes to pop up all over the planet. Eventually the pressure builds so much that it all releases in a “resurfacing event.”

It is exactly as violent as you might expect the changing of the entire surface of a planet to be.

The current surface of Venus is estimated to be between three hundred and six hundred million years old. Some day it will get a new one, and everything you’ll see before you, including that granite lounging spot, will be gone.

Venus has had many different surfaces in its past, including a surface that might have looked quite familiar.

Think about that granite rock.

To make granite, you need water. But there is no water on the surface. Even the pure acid rain that falls on Venus evaporates long before hitting the rock.

Recent evidence from both rock and sky (including the incredibly high amount of deuterium in the atmosphere) on Venus suggests that the planet once had oceans. And not briefly, but for perhaps as long as two billion years. Half its lifetime it could have been a habitable planet.

But that time is long gone, destroyed by a runaway greenhouse effect. The result is an atmosphere that traps enough heat to make Venus the hottest planet in the solar system by a huge margin. It doesn’t matter that Mercury is closer to the sun.

But most details of that potentially watery past have been swept away by a planetary surface that will continue to change.

Just something to think about while you sit, have a coffee, and watch the lava flow.

Image 2: Three-dimensional perspective view of the Alpha Regio region on the surface of Venus. The simulated hues are based on color images recorded by the Soviet Venera 13 and 14 spacecraft. The image was produced at the JPL Multimission Image Processing Laboratory by Eric De Jong, Jeff Hall, and Myche McAuley.

Image 3: NASA computer generated three-dimensional perspective view of craters Saskia (foreground), Danilova (left), and Aglaonice (right). The image was created by superimposing Magellan images in topography data, and coloring is based on Venera 13 and 14 Lander images.

Earth’s solar system contains hidden wonders for the enterprising cosmic adventurer to discover. For example, if you were to visit your near neighbor Mars, the more obvious spot is Olympus Mons.

Olympus Mons is obvious because Olympus Mons is big. Ridiculously big. The colossal mountain stands over three times as tall as Mount Everest, Earth’s highest point above sea level.

As its slope only rises at an average of 5°, the entire mountain covers roughly 300,000 square kilometers. Olympus Mons is bigger than the whole of New Zealand.

It is quite a sight, but Olympus will no doubt become an exceedingly common tourist destination. The need to stand at the highest point is already a problem on Earth. Over 3,000 individuals have combined for a total of over 5,000 ascents to the summit of Mount Everest. Environmental destruction is significant problem and there are now expeditions for the sole purpose of cleaning the mountain of rubbish from previous expeditions.

Olympus Mons is the largest mountain on any planet in the solar system by a tremendous margin. (In fact, Mars is home to the four tallest: Olympus, Ascraeus, Elysium, and Arsia.) The moment travel to Mars becomes a practical reality expect the great mountain to become a dumping ground.

Our recommendation? Stay off the beaten path. We say if you want mystery and adventure, don’t go up, go down! Down, down into the hidden depths of the Red Planet… and into the Valles Marineris!

Named for the Mariner 9 space probe that orbited Mars in 1971, the great canyons stretch for nearly a quarter of the planet’s diameter (over 4,000 kilometers). But to enter this great chasm, one must navigate Noctis Labyrinthus…

The Labyrinth of the Night.

The far western reach of the Valles Marineris begins with not one grand canyon but hundreds of smaller canyons that run through each other, creating a massive maze.

We recommend visiting just before sunrise for a truly spectacular experience.

The Martian sunrise appears quite the opposite of Earth’s. Rather than red around the sun and blue in the sky, the iron-rich dust in the air makes the sky red and the area around the sun is a blueish purple.

As you descend into the the Labyrinth, the rose-colored sky above will disappear into a thick fog. You’ll find the criss-crossing canyons of Noctis Labyrinthus filled with mist, a white haze caused by frost sublimating in the early-morning sun. The clouds cling to the low canyon areas and only rarely spill over onto the plateau surface, creating a stark difference in your view, whether you are on the lip, staring into the mist… or if you travel into the Labyrinth itself. Don’t get lost!

Adding to the confusion: the floor of the Labyrinth is an ever-shifting pattern of dunes that form complex structures.

Along with plenty of iron(III) oxide, you’ll find a high abundance of elements with low boiling points, such as chlorine, phosphorus, and sulfur. The stochastic (rather than a deterministic) process in which the solar system formed gave each planet its own flavor.

The flavor of Mars is rust. But though it appears a uniform clay color from orbit, at ground level you’ll find beautiful streaks of red, white, black, green, and gold.

The entire Valles Marineris looks as if some great claw extended from the Martian sky. Or as the result of a glancing blow of some ancient kinetic impactor. In reality, the valleys were ripped open along tectonic plates.

But though Mars is a place of great rifts and great volcanoes, there is very little active volcanism today… which reminds us, in addition to dealing with the thin atmosphere (one percent the thickness of Earth’s), proper radiation shielding is critical on Mars.

Mars has no magnetosphere because the planetary dynamo has long since stopped. Earth’s magnetic field comes from circulating currents in its liquid metal core. But’s dynamo stopped ground to a halt roughly four billion years ago.

When solar radiation hits Earth’s magnetosphere, you get the Northern Lights. There are no Northern Lights on Mars.

Perhaps there will be some day. Humans have about a billion years to get Mars’ dynamo started (or find some other, more pragmatic way to provide protection).

Being in roughly the middle of its ten-billion-year lifespan, the Sun has about five billion years left. But as it consumes its hydrogen fuel, it will get hotter. Earth has about one billion years of livability, assuming a number of other factors haven’t rendered the planet unlivable beforehand.

Not only could humans live on Mars in the relatively near future, someday Mars could be humanity’s home planet.

It will be a different Mars. Perhaps warmer due to the sun. Perhaps warmer because human-introduced plant life converts the 95-percent carbon dioxide atmosphere into a breathable biome. Ice would melt, filling valleys and converting the crisscrossing canyons into waterways.

For now, the Labyrinth of the Night sits shrouded, waiting to be explored.

No doubt you’ve discovered your Earth is but a small stage in a vast cosmic arena. This may give you the desire to strike out your own and go where the solar wind takes you.

But let’s not get too ambitious just yet. You don’t want to find yourself in the wrong arm of the galaxy. Before we start star-hopping, let us begin a bit closer to home. After all, there’s so much to see in just your own solar system. And ever closer.

Many of you already have been to your moon, Luna. (Yes! Like the planets of your solar system, it does have a Latin name, though “The Moon” is acceptable, which is fair I suppose since it’s the only one you’ve got.) Indeed, it is the most commonly visited location by humans outside of Earth. Of course, it’s the most commonly visited location because it is the only place you’ve been.

But what a place! Just listen to these testimonials from past Moon visitors:

“As I stand out here in the wonders of the unknown at Hadley (lunar region), I sort of realize there’s a fundamental truth to our nature. Man must explore. And this is exploration at its greatest.”
–David Scott, Apollo 15 transcript

“I think the thing that impressed me the most was the Lunar’s sunrises and sunsets. These in particular bring out the stark nature of the terrain… The horizon here is very, very stark, the sky is pitch black and the earth, or the moon rather, excuse me, is quite light, and the contrast between the sky and the moon is a vivid dark line.”
–Bill Anders, Apollo 8 telecast from lunar orbit, December 24, 1968

“From out there on the Moon, international politics look so petty. You want to grab a politician by the scruff of the neck and drag him a quarter of a million miles out and say, ‘Look at that, you son of a bitch.’”
–Edgar Mitchel, Apollo 14

With so much to see on just your moon, what spot should you pick for your visit? Our recommendation: Copernicus!

Copernicus a massive crater near the center of the “Ocean of Storms.” (Look at the Moon; the Ocean of Storms is that really big dark splotch on the left). It’s not an ocean in the sense you’re used to. The mass of dihydrogen monoxide that covers most of your planet moves. This ocean doesn’t, though some ancient astronomers thought it did. They were accidentally right in one sense. At one point the Ocean of Storms did move because the darker portions of Luna are solidified pools of ancient basaltic lava.

The surrounding basalt plains highlight the size and complexity of Copernicus. It is ninety-three kilometers wide, with walls reaching four kilometers into the black sky. Those walls are terraced, creating a complex overlay of rock expanding out in concentric circles that crest and then fall into a thirty-kilometer-wide rampart descending to the “ocean” floor.

The rough edges at the rim of the crater can cast long, beautiful shadows when the sun is just right. And with no air to scatter light, these are shadows of pitch black, like blades of nothing creeping across the crater floor.

Travel tip: Be careful where you stand! There is a 250-degree difference between sun and shade on the Moon (roughly 100 degrees C and –150 degrees C). We advise proper hot and/or cold gear depending on the time of moon-day. We would also advise against jumping back and forth between shade and sun, as it will do little to solve the problem.

Of course, that might cause you to work up an appetite! If you’re looking for a great place to picnic, we suggest choosing one of the three mountains that formed in the center of the crater following impact. The tallest stands more than a kilometer high and should provide great views of the surrounding lunar landscape.

Wherever you sit for your meal, do be careful not to disturb the ground too much. Due to the preserving vacuum of space, every footprint is permanent. So at least bring a blanket to sit on, avoid accidental trampling, and please, please, please resist the temptation to leave intentional markings. The luminous immortals that will replace the human race eons in the future need not know that “Jeff wuz here.”

This is not to say the surface of the moon never changes. Indeed, Copernicus’s serrated edges and pristine peaks are present because it was so recently formed… only eight hundred million years ago! (Give or take.) It came to be when an asteroid struck the moon, sending volcanic basalt flying over eight hundred kilometers from the point of impact. Falling ejecta from the initial blast created thirteen surrounding craters of three kilometers or greater in diameter… giving you plenty of interesting features to look at!

Like most rocks in most solar systems, Luna has a violent history. The Moon itself was created by a great impact. Most evidence on the subject points toward a massive collision between your Earth and an object roughly the size of Mars that occurred approximately four and a half billion years ago, not long after the Earth first coalesced out of the protoplanetary disk surrounding the young Sun. Thus Earth, thus Moon, thus Copernicus, thus your next vacation destination.

If you travel to Copernicus, you’ll be the first of your species, or any species, to stand on that spot (and, obviously, also the first to have a nice lunch on that spot). This was nearly not the case. The crater was a possible landing site for the canceled Apollo 18 mission. Apollo 17 was the last to visit the Moon and no human has set foot on Earth’s natural satellite since 1972.

It is also an appropriately named place to begin our journey. The crater is named for Nicolaus Copernicus (1473 – 1543). The Renaissance mathematician was the first to create a fully predictive model of the Universe that did not have Earth at its center.

He was not the first to speculate this. The earliest known scientist to present a heliocentric (sun-center) model of the Universe was ancient Greek astronomer Aristarchus of Samos (c. 310 – c. 230 BCE). But Copernicus was the first to create a workable model with the Sun squarely in the center.

The Sun is, of course, not the center of the Universe. Due to its expansion from a singularity there is no “center of the Universe.” But Copernicus’s work was a key first step to understanding that the Earth is not the center… that you are not the center.